Generally, an ignition switch-steering column lock assembly serves as an electric switch that initiates cranking of the engine via a sequential conversion of four positions including; LOCK, Accessory (ACC), ON, and START. The assembly also locks the steering column for theft prevention while in the LOCK position. The ignition switch-steering column lock assembly further has a key interlock function that prevents the key from being removed from the ignition switch-steering column lock assembly unless the vehicle is in a parked state, thus deactivating the steering column lock function when the vehicle is in motion.
Typical key interlock systems include a cam that rotates according to the rotation of the key cylinder and an electrical actuator restrains the rotation of the cam and the range thereof. The key can be released from the key cylinder only when the key cylinder is in the LOCK state, and the electrical actuator restrains the rotation range of the cam for allowing the key cylinder to pivot in the LOCK state only when the vehicle shift lever is in the Park (P) state.
The electrical actuator can be either a unidirectional solenoid actuator or a bidirectional solenoid actuator. The unidirectional solenoid actuator uses magnetic force from an electromagnet for one-way linear movement of the plunger and the other linear movement thereof relies on force generated from a spring. The bidirectional solenoid actuator applies the magnetic force of the electromagnet to linear movements of the two-way directions thereof.